Spark plug



Nos?. s, 1927.

M. JACOBS SPARK PLUG Filed March 2, 1926 Mam Z@ @0056;

@Mummia enemies Nev. s, i927. f

1,948,779 PATENT FFCE.-

MURICE JACOBS, 0F TUCSON, ARIZONA.

SPARK PLUG..

Application 1ed March2, 1926. Serial No. 91,763.

rihe invention relates 'to improvements in spark plugs for internalcombustion engines, and it is my object to provide a new and improvedplug construction, in which novel provision is made, permitting theelectrodesV p of Fig. 1.

I illustrates one advantageous constructiom. and this construction 'willbe here-1n spe-l Fi 3 is a horizontal section on line 3-3 of Figs. 1 and2. While the drawing above briefly described,

citically described, it is to be understood at the outset, that Withinthe scope of the invention 'as claimed, numerous variations may be made.

The numeral having the usual flat-sided.' portion 5 for engagement witha Wrench, and cylindrical,

externally threaded portions 6 and 7 pro-I jecting in oppositedirections from said portion 5, the portion-6 being adapted forreception in the usual spark 'plug opening of Aa. cylinder head, whilethe portion 7 is received Within a continuous shell cap 8. 'The shellbody 4 and the cap 8 are so shaped as to effectively secure an insulator9 inplace,

` the usual gaskets 10 being employed.

The shell body 4; is divided on lines 11 extending` longitudinallythereof, into two co-operable sections 12, which sections are heldtogether by the shell cap 8 and by the.. cylinder head, when the sparkplug is threaded into the latter. To assist in assembly,- the sections12 may be provided with anydesired positioning means,` such asintertitting tongues and grooves 1ER-14.

A grounded electrode'l is provided,'hav

ing an attaching portion 16 which is tightly held between thesections12, but-is readily f removable when these sections lareseparated from each other by 'unthreading the plug 'from the cylinderhead and removing the shell cap 8. `The attaching portion 16 is shown inthe form of' a wedgeshaped head,

4 designates a shell body and opposed surfaces of the sect-ions l2 areformed With angular notches 17 snugly receiving said head.' Thesenotches open through the inner end of the shell portion 6, throughthe-.exterior of this lportion and through the interior thereof, in thepresent disclosure. Hence, the shell andthe attaching portion 16 arepro-vided with cooperablemeans to hold said portion 16 against movementtoward either the exterior or the interior of the shell. Thesecof-acting means may Well consist of Vstuds 18 on the attaching portion16, and sockets 19 in the shell sections 12, said sockets receiving.said studs.

Preferably, the free edge of the shell portion 7 is formed With notches20 at the ends of the lines 11, facilitating the insertion of a knifeblade or the like to separate the shell sections 12, if they havefbecomestuck toget-her by carbo-11 o-r the like, after along period of use.

A metallic memberis embedded longitudi-y nally -in the insulator 9 andembodies a tubu lar inner portion 21, an outer portion 22 extending ytothe outer end of the insulator land constituting a'binding post, andv anenlargement 23 Withinthe portion ofthe insulator surrounded by the heavyintermediate portion 5 of the shell body i,the three'portions 21, 22 and23 being preferably integral With each other as shown.

' The tubular .portion 21 extends t0 theinnerend of the insulator 9 andis gradually increased in' diameter toward said end. A central electrode24 is snugly received in this tubular portion 21, being` vlongitudinallyta ered both for 'tight wedging engagement wlth said tubular portion,and to provide the electrode vwith an enlarged portion which projectsbeyond the insulator and is provided with fiat surfaces 25 to be engagedby a Wrench or other suitable tool. threads-26 are provided forconnecting the smaller end of the electrode 24,- with the portion 23 ofthe metallic member 21-22-23'.

Screw- By using a wrench or the like' up0n the fiat l faced portion ofthis electrode, it maybe tightly threaded and wedged. into operativeposition so that there is no danger of it becoming accidentallydetached. Whenever the sparking point 27 o f this electrode has becomeso Worn as to be ineicient, the portions 25 may be engaged with a Wrenchor the like and the entire electrode removed. Then, a new electrode maybe substltuted.

As the wear on bo-th electrodes 2415 1s uniform, both of them should berenewed at the Sametime, but this may not in all instances be necessary.

Itwill be seen from the foregoin that I have provided a new and improvespark plug lconstruction in which the majority of parts may be usedthroughout the life of the machine on which it is employed, unlessbreakage of the insulator 9 should' acciden-v tally occur. Theelectrodes however, may be renewed from time'to time and after suchrenewal, the plug isjust as eiic'ient as a new u Attention is againinvited to theI fact that within the scope of the invention as claimedvarious modifications may be made.

I claim the following as newly invented with respect to spark plugs 1. Aspark plug comprising a shell externally threaded for engagement -withthe usual spark plug opening of a cylinder head,l

between said abutting edges'of said sections,

said additional electrodel being removable upon separation of saidsections.

2. A spark plug comprising ashell body externally threaded forengagement with the usual spark plug opening of a cylinder head, saidbody being -divided into sections meeting on lines crossing the screwthreads, an

.insulator removably held between said sections and carrying anelectrode, a shell cap threaded upon the outer end of the shell body andholding said sections against sepan ration prior to threading of theplug into the opening, and an additional electrode free of connectionwith said insulator and lhaving an attaching portion rigidly heldbetween said shell sections, said additional electrode being removableupon separat-ionof said sections after removal of said cap.

3. A structure as speciied in claim .1;

said attaching portion of the electrode being inthe form of an enlargedhead, said abutting edges 4olf said shell sections being rek cessed fromthe interior to theexterior of the shell to receive said head, said headand shell vhaving co-acting" meansy to prevent .movement of said headtoward the interior or exterior of the shell while the shell sectionsremain assembled.

MAURICE JACOBS.

